Seats for Vehicles, for Example, Sports Vehicles Such as Go-Karts and the Like

1. Field of the Invention

The present invention relates to seats for vehicles having a receiving structure which can receive at least part of a user's body.

The invention has been developed with particular concern for its possible application to sports vehicles, such as go-karts and the like.

2. Description of the Background Arts

In this field of application (to which explicit reference will be made below in the present description although this should not be interpreted as limiting the scope of the invention in any sense), there has always been a tendency to use simple bodies and shells of rigid material for the seats. This has been as much for practical reasons (to minimise weight) as for the desire to make the vehicle simple and spartan in view of its function as a competitive vehicle.

With the continuous improvements in the performance of such vehicles there is, however, a corresponding increase in the forces experienced by the driver's body as a result of accelerations, with the consequential possibility that the performance may be limited.

In the context described above, the use of solutions which are already known in the field of conventional motor-vehicle seats (for example: quantities of padding of various types, associated spring elements, etc.) does not provide an answer to the problems stated above. Usually these conventional solutions require the adoption of more or less fixed structures which are just as difficult to adapt to the different anthropometric characteristics and/or habits of the individual sportsman as to the different conditions of movement.

The object of the present invention is to provide a solution to the requirements indicated above while overcoming the limitations intrinsic in prior art solutions.

According to the present invention, this object is achieved by means of a seat having characteristics as in the claims which follow.

The invention will now be described, purely by way of non-limitative examples, with reference to the appended drawings, in which;

FIG. 1 is a general perspective view of a seat according to the invention, and

FIG. 2 shows a system for the automatic control of the characteristics of a seat according to the invention with reference to a currently preferred embodiment.

In the drawings, a vehicle seat is generally indicated as 1.

The specific embodiment shown is concerned with a seat for a motorised sports vehicle such as a go-kart; however, other fields of application can be envisioned.

In accordance with a known solution, the seat 1 comprises a shell 2 of a material such as a light metal or, more preferably, a structural synthetic material such as a glass fiber reinforced resin, plastics a material, etc., defining a shell-shaped structure which, as a whole, is rigid and can be fixed (according to well known criteria) to the vehicle body. As shown schematically in FIG. 1, the body can be in the form of several tubes which make up the frame of a go-kart (not illustrated in its entirety). The definition of the structure of the shell 2 as being "as a whole" rigid is intended to indicate that this structure may possibly include more or less flexible parts. What matters, however, is that this structure is rigid overall so that its concave side, which faces upwardly in use, can receive at least part (typically most of the trunk and proximal portions of the lower limbs) of the body of a passenger (such as, for example, the driver of a go-kart).

The shell 2 is shaped so that the seat 1 has a seat proper 3, a backrest 4 and two sides 5 shaped so as to give the seat 3 and the backrest 4 a generally channel shape so as, effectively, to contain the driver's body laterally. The shell 2 thus defines overall, a shell shape with a concave inner surface which can receive at least part of the user's body.

In a preferred solution (also known per se), the seat also has two front appendages 3a which project forwardly so as to provide good support for the popliteal region the driver's legs.

The solution of covering at least the inner surface of the shell 2 intended to receive the driver with a covering of a material such as "alcantara" is already known. This is as much for aesthetic reasons as for providing a certain degree of friction with the driver's body so as to prevent him from slipping on the seat, particularly due to accelerative forces which arise during movement of the vehicle.

A salient characteristic of the solution of the invention is the provision of at least one selectively inflatable cushion element in the region of the seat intended to be between the shell 2 and the driver's body (that is, on the inner surface of the shell 2), the cushion being inflatable by a fluid, preferably a gas.

In the currently preferred embodiment, three cushion elements of this type are provided. More precisely, two cushions 5a are located one against the upper part of each of the sides 5 (thus on the sides of the backrest 4) and a third cushion 4a extends horizontally along the upper part of the backrest 4.

Preferably, the cushions 4a, 5a (constituted for example by inflatable pads made of a material such as that used for the inner tubes of tires) are interposed between the shell 2 and the cover 2a. With this arrangement, one or more holes 6 can be present in those parts of the cover itself which cover the cushions. The purpose of the holes 6 is to allow air to pass through the cover 2a, avoiding the formation of "free" air cushions, that is, different from the cushions 4a, 5a, between the cover 2a and the shell 2.

The purpose of the cushions 4a, 5a is to form padding between the generally rigid structure of the seat 1 (i.e., the shell 2) and the driver's body. These cushions have both the function typical of padding (absorbing forces which can arise during movement) and that of holding the driver's body more precisely and effectively in the seat 1.

In the simplest embodiment, that to which FIG. 1 refers, the cushions 4a, 5a are constituted simply by pneumatic pockets, each of which may be inflated selectively, for example with the aid of a pump, through a respective valve 7 (only one of the valves is visible in FIG. 1), such as a valve commonly used for the inflation of pneumatic tires.

Each cushion may in turn be constituted by a single air chamber (inflation chamber) with a respective inflation valve or by a plurality of air chambers, preferably independent from each other and each having a respective inflation valve. The provision of several independent air chambers has the advantage of enabling each air chamber to be inflated differently according to its spatial location in the seat (and thus according to its position relative to the driver's body) so as to achieve a specific volume and/or a specific inflation pressure, and hence a specific rigidity, according to the requirements in use.

The solution of the invention thus starts from a generally standard seat structure 1 (shell 2 and cushions 4a, 5a) and--through selective inflation of the cushion--becomes a seat which, on its inner surface intended to receive the driver, has its conformation and characteristics of rigidity adapted, even locally (particularly when each cushion is constituted by several air chambers), to the specific anthropometric characteristics and/or tastes of the individual occupant.

The inflation of each cushion to a greater or lesser extent (i.e., to a greater or lesser pressure) also enables the seat 1 to be adapted to different requirements of use, for example to accord with differing track characteristics, to provide a choice, for example, between a generally softer, less restraining seat (cushions inflated to a "low" pressure) and a harder seat which clamps the driver's body more firmly (cushions inflated to a "higher" pressure).

The solution illustrated in FIG. 1 may be defined as static in the sense that--in general--it provides for the inflation of each cushion 4a, 5a to a desired pressure (for example with a pump) before the seat is used.

The schematic drawing of FIG. 2 shows, in one possible variant, how the invention also lends itself to being embodied in a dynamic configuration in which the degree of inflation (pressure) of each cushion 4a, 5a may be varied selectively, even during driving, and thus even when the seat 1 is occupied by the driver, for example during a sports competition.

The embodiment of FIG. 2 provides for the cushions 4a, a to be connected to a source 8 of pressurised fluid (typically pneumatic, although pressurised liquids may be used in certain cases--at least for some cushions or portions thereof) with the interposition of respective valves (solenoid valves) 9a, 10a (there are two of the latter since two cushions 5a are provided, one for each side 5 of the seat) controlled by a single processing or control unit 11.

FIG. 2 refers, for simplicity, to a solution in which each cushion 4a, 5a is individual in the sense that it comprises a single air chamber. It goes without saying that, if one or more of these cushions includes several air chambers, (such as 4a' shown with broken lines in FIG. 2) the solution of the invention may involve the provision of a corresponding number of solenoid valves.

In general the cushions 4a, 5a are initially to a reference pressure and then, during travel, by operation of the solenoid valves 9a, 10a the inflation pressure may be varied at will, both to increase it (by opening the solenoid valves 9a, 10a to positions in which the respective cushions are put in communication with the pressure source 8) and to reduce it (the valves 9a, 10a being switched to the positions in which the respective cushions are put in communication with a vent line to the exterior).

For this purpose, the solenoid valves 9a, 10a are typically valves which each have three connectors or ways: to the pressure source 8, to the respective cushion and to a vent outlet typically to the atmosphere.

All of this allows the selection of three operative positions, that is to say:

a closed (position with all three ways closed), the inflation pressure of the cushion being kept constant,

a connection position with the pressure source 8 connected to the respective cushion 4a, 5a so as to increase the pressure to which the cushion is inflated, and

a vent position with the pressure in the cushion vented to the exterior with a consequent reduction in the inflation pressure.

Although the following may be more complicated from an operational point of view, it is possible to provide for the pressurised fluid resulting from the venting of one cushion not to be simply discharged to the exterior. It is in fact possible to connect the various solenoid valves together, at least temporarily, (connections indicated schematically in broken outline by the reference 100 in FIG. 2) so that the pressure vented from one cushion is used at least partly to increase the pressure in another cushion. This is the case, for example, in solutions which provide for the control of the unit 11 by accelerometric signals (as best seen below), with the consequent possibility that the excess pressure resulting from the reduction in the inflation pressure of the cushion 5a on one side of the seat is used to increase the inflation pressure of the cushion 5a on the opposite side.

With regard to the pressure source 8, it is possible to use various solutions, particularly when one is dealing with a pneumatic source.

For example, the source 8 may simply be a cylinder. This solution has been shown to be advantageous particularly in those cases in which weight and bulk are determining factors.

Alternatively, the source 8 may be constituted by, or at least include, a compressor, preferably with an associated pressure accumulator. This solution, at least in some applications, may be exacting in terms of weight and, in particular, in that it will drain a degree of power from the propulsion unit of the vehicle. The solution of the invention, however, lends itself to the use of a compressor which can be activated, for example, only during the deceleration of the vehicle. In this case, as well as not draining useful power from the propulsion unit, the compressor can cooperate with the vehicle's braking system in effecting the deceleration.

With regard to the control unit 11 which governs the activation of the solenoid valves 9a, 10a (and hence controls selectively the inflation pressure of the cushions 4a, 5a), this may be an electronic control unit (of a type known per se) which can be controlled by the driver (for example by push-buttons on or adjacent the steering wheel).

In the currently preferred embodiment, the unit 11 is arranged to operate automatically in dependance on signals from two accelerometric sensors 12a, 12b mounted on the vehicle and in general sensitive to:

accelerations forward and rearward of the vehicle (sensor 12a); and

accelerations transverse to the vehicle (sensor 12b).

These types of sensors include known accelerometric sensors, known particularly from the aeronautical field in which they are currently known as G-meters.

More particularly, the unit 11 may be programmed so that during a strong forward/rearward acceleration of the vehicle (for example as a result of a sharp acceleration such as that which occurs during the starting phase of a competition or during a resumption of driving), the signal produced by the sensor 12a (through) the unit 11 and the valve 9a) causes an increase in the inflation pressure of the cushion 4a which is at the top of the backrest 4. Thus, it is possible to avoid the driver's back being squashed against the shell of the seat 2 since the cushion 4a is interposed like elastic padding between the shell 2, itself, and the driver's back. Once the strong acceleration has ceased, the inflation pressure of the cushion 4a may be returned to a normal reference value (selected by the driver) so as to achieve the appropriate padding for normal driving conditions.

The same solution is adopted for the side cushions 5a. When the vehicle is moving in a straight line, these are kept at a uniform pressure (the cushions possibly being at different pressures if so desired by the driver) and the pressures are then increased selectively when the vehicle changes direction and the driver's body is thrust sideways--by centrifugal force--towards one side 5 of the seat 1. The sensor 12b detects the strength and direction of the centrifugal acceleration and acts through the solenoid valves 10a to increase the inflation pressure of the cushion which is compressed at that moment between the driver's body and the side 5 towards which the driver's body is thrust. More particularly, in the case of a zig-zag path, the inflation pressures of the cushions 5a on the two sides are modified alternately, with the possibility of using at least some of the excess pressure discharged from one cushion to increase the pressure in the cushion on the opposite side (line 100 in FIG. 2).

Naturally, with the principles of the invention remaining the same, the constructional details and forms of the embodiments may be varied widely with respect to that described and illustrated without thereby departing from the scope of the present invention.